Many modern antenna applications require high bandwidth, dual polarization array antennas. In addition, many of these applications also require low cross polarization between antenna elements. A further desirable quantity is for the elements of an array antenna to have coincident phase centers for different polarizations to reduce the need for complicated polarization calibrations. It is also generally desirable that antenna designs be relatively easy and low cost to manufacture. Due to size and weight constraints in some applications, it may also be desirable that antennas be lightweight and relatively low-profile. Thus, there is a general need for antenna designs that are capable of providing some or all of these various attributes.